This application claims the priority of Korean Patent Application No. 2003-87474, filed on Dec. 4, 2003, in the Korean Intellectual Property Office, the contents of which are incorporated herein in their entirety by reference.
1. Field of the Invention
The present invention relates to a semiconductor device, and more particularly, to a semiconductor device having a sense amplifier driver that can minimize the influence of an off current in high-temperature fast processes and a method of generating a sense amplifier enable signal while minimizing the influence of an off current.
2. Description of the Related Art
FIG. 1 is a schematic diagram of a conventional memory cell used for a semiconductor memory device. Referring to FIG. 1, the memory cell 10 is made up of a transistor 11 and a capacitor 12.
In general, the gate of the transistor 11 is connected to a word line WL, one node of the transistor 11 is connected to a bit line BL, and the capacitor 12, used to store data, is connected between the other node of the transistor 11 and the ground voltage VSS.
With the development of deep submicron technology, the threshold voltage of the transistor 11 is getting lower to improve performance of the transistor 11. The performance of the transistor 11 can be expressed by the amount of current Idsat that can flow through the transistor 11 at a turn-on state.
However, if the threshold voltage of the transistor 11 is lower, the amount of current Idsat that can flow through the transistor 11 at the turn-on state (hereinafter, on current) increases. Also, the amount of leakage current Ioff flowing through the transistor 11 at a turn-off state (hereinafter, off current) increases.
In general, the off current Ioff changes according to temperature, voltage, and a manufacturing process used in making the transistor. Processes include a fast process and a slow process. For example, a transistor in which the on current Idsat is large can be manufactured in the fast process, and a transistor in which the on current Idsat is small can be manufactured in the slow process.
However, under specific conditions (for example, a high temperature and fast process), the off current Ioff increases so much as to affect the on current Idsat. Particularly, in an array type with a plurality of memory cells, a merit obtained by lowering the threshold voltage of the memory cell dramatically decreases due to the difference between the on current Idsat and the off current Ioff in the high temperature and fast process.
When a memory device having a memory cell is designed, a limitation where threshold voltage of the memory cell can be lowered exists due to the off current.